Guild Wars 2

If I do Heart of Thorns story line solo, I have no problems. I get occasional Mastery Points and the end of the story mission crossed blades icon with bonuses. I am having issues with getting credit while I do the story line with other players. If the other player begins the mission, and I happen to do a story line out of sequence I get no credit. I have also not received credit on at least one occasion for doing the story line IN SEQUENCE but not having started the mission. Is there somewhere where I can read about how this works ?

Thanks,
:-)

start the storyline mission yourself. problem solved.

You need to do it in sequence, and you need to be on the same step as them. You need to hit accept credit at the end. All the outside of the instance steps need to be done alone.

Normally, you get a pop up window saying something like “You have the choice to get credit for doing this story step, too, even if you haven’t opened the instance” after you’ve finished the instance.
The not-in-sequence part is intended to not count for you I guess, since PS (vanilla and HoT) seems to have a forced order, unlike LS chapters.